I was inspired to create this post not by Alice Cooper (great song BTW) but by a particularly bad streak of shoddy work I’ve run into over the last while. Now every watchmaker will have a bad day (we are human after all), but some of the things I see come into my shop that have been done by others sometimes boggles the mind.

I thought I would show some partly for entertainment purposes so you can see the things that I run into, but also knowing that we have some amateur watchmakers here they might learn what not to do from some of these examples.

The first example I’ll show is a vintage Speedmaster with a Cal. 861. Came in with a few issues, so not running well, stem bolt for hammer was missing so it would reset the chronograph when you tried to stop it, it had hour recorder creep, there were a few worn train wheels that needed replacing, etc. Nothing terribly unusual for a vintage Speedmaster, but something did catch my eye during disassembly – you can see a streak of black around the ratchet wheel with the main bridge removed:



And an unusually large amount of swarf around the hole in the bridge for the barrel arbor:



So since this watch (like most modern watches) uses a going barrel design, the only time the barrel arbor is actually turning is during manual winding of the watch, so wear like this isn’t all that common. But this is where the poor work practices of a previous watchmaker come into play. Looking at the barrel arbor, I can see someone has handled it quite poorly:



It looks like the arbor was mishandled with stout carbon steel tweezers, maybe when removing or installing it from the barrel, and the damage done it quite extensive. It basically turned the smooth arbor into a drill that ate away at the bridge. A close look at the bridge after running it through the cleaning machine reveals the hole is worn oval in the bridge:



This allows the barrel to tip off perpendicular, causing binding, loss of amplitude, and as you can see 2 photos above there is a fair bit of wear on the underside of the barrel bridge from the ratchet wheel. The arbor was replaced, but replacing the bridge is not a cheap proposition, as a new one is a few hundred dollars. The key part of repairing this is maintaining the centerline of the original hole, not the worn hole. There’s no point in installing a bushing if it’s off center and will tip the barrel anyway after the repair is done. If you look at that photo of the bridge again though, you can see that the oval portion of the hole is only part way through the bridge material, and the rest of the hole is still round and in good condition below that red line I've added. Now if the hole was oval through the entire thickness, a repair would be more involved – likely would use a faceplate on the lathe, using the main plate and hour recorder bridge to find the center of the worn hole, then bore it out and install a bushing. In this case since I have a good amount of the original hole to act as a pilot, I can ream the worn hole out using my Seitz tool:



The first reamer was done from the non-worn side (forgot to take a photo of that) so I was properly located on center using the good portion of the hole as the guide for the reamer – I reamed out the hole large enough that the worn portion was removed. I then slowly stepped up reamer sizes a bit larger each step:





Now I’m at a size where I can fit a bronze bushing in the plate:



And for that I use the Horia jewelling tool:



Here the bushing is installed:



The inner diameter needed to be reamed to fit the new arbor:



Bridge was cleaned again, and the assembly was completed:



It’s now in final testing before being returned to it’s owner:



So a fair bit of extra work, just from damage caused by handling the barrel arbor improperly. By the way, I use bronze tweezers for most general assembly work, and for barrel arbors specifically there are barrel arbor holders that are like pin vices, but come in different sizes to allow easy fitting of arbors back in the barrel:



I'll post more another time...

Cheers, Al

 

I love these watchmaker posts.... more please.

 

Thanks for posting Al. Do the bushings come in different lengths or do you need to trim them to fit the profile of the bridge/plate?

 

Interesting article. I have no real understanding of how complicated watch mechanics are, but I do appreciate reading about it. More importantly it highlights the importance of getting a recommended watch maker. Not esay without a little bit of guidance.

 

Yeah thanks Archer, so interesting.

 

Great post Archer, I barely understand how my watches work but was able to follow most of your explanation, and the photos are gorgeous too!

 

Very interesting, thanks Al. A neat way to save that bridge and very clear write up.

I'm using brass tweezers for virtually everything but they are very soft. I suppose the bronze ones won't mark as well and are somewhat harder than brass so should maintain shape better (less dressing?) and you can get them in a finer tip?

More of the same if you have time, thanks!

Cheers, Chris

 

These are bushing specifically for watches, so I can't recall having to cut one down for thickness before. The specific bushing here was from a Cal. 501 actually...

Bronze are harder than brass, and yes they go longer between dressings, but the primary reason I use them over brass is the feel. Coming from using steel tweezers for years, you get used to a certain amount of "spring" in the tweezers as you use them, and the brass felt sort of dead to use, where the bronze feel more like steel. Both brass and bronze are better for handling parts as they don't tend to fling parts like steel can.

Cheers, Al

 

And for my 200th post I shall simply say "WOW I want to send all my future maintenance needs to @Archer!" Impressive both in explanation and photography.

 

Here's another example - PAM112 that came in recently with poor timekeeping. I fully wound it and placed it dial down on the timing machine, but the watch would not even bring up a reading, and the message on the machine indicates we might have a problem:



Flipped it over after a while so dial up I get a reading, but amplitude was high, and it was knocking (rebanking):



Here disassembled, and most things looked okay, except the mainspring looked odd...



To compare, I had another watch with the same movement in that I just finished servicing, so these are the two old mainsprings from each watch - quite a difference:



End of this spring shows that it has been modified to work since this is not the normal tang end:



Looks like the arbor end had heat applied to it to reform the end, and it was all very much out of flat:



I measured the spring and it was far too thick/strong, so someone had just taken some fairly random spring and "made it work" rather than buying a new proper spring. When I say too strong, here is what the proper spring for this watch measures for thickness:



And here is the one removed:



To many of you that won't seem like much, but consider that the strength of the spring is proportional to the cube of the thickness. If you double the thickness, the spring is 8 times stronger (2 X 2 X 2). So even one hundredth of a mm difference in thickness is huge, and this is about 5/100ths thicker than it should be.

So in addition to the spring being a problem, the barrel was all hacked up, likely from trying to manipulate the spring while it was installed in the barrel:



A closer look shows how badly the floor of the barrel drum is damaged:



I replaced the spring, barrel, and did the service, and it ran fine after that.

Cheers, Al

 

Impressive post @Archer as always.

Very informative.......and relieved not to see my watch there

 

Thanks and I'm glad you enjoyed the post. I will say though that as much as I appreciate the idea that all watches should come to me for servicing, that's not why I'm doing this. I already have more work than I can handle, so I'm not soliciting more work in this thread!

The reality is that the things I'm going to show that have gone wrong are pretty much "watchmaking 101" and they are just about doing the basics right.

Cheers, Al

 

Yet!

Just kidding!

 

Thank you for allowing us a window into your work! There is much that can be learned through your explanation of your thought processes.

 

Got halfway through the post before I realized that is my Speedmaster. Happy to see that issue got resolved.

I'm kind of surprised the watch has been serviced at all. My guess is it was done by the original owner sometime back in the 90s. When the original owner passed away, the watch went to his son and then was sold to one of the son's coworkers. It sat in a drawer for a number of years before I bought it. Even after that, I didn't wear it much since I knew it was (over) due for service.

I wonder how much worse things would have been if I had actually worn it regularly (although the damage is already done, I guess).

 

Haha.......heart palpations have settled now....i think

 

Indeed, it's in the best place for it

 

Is that a 6497 base? If so, a spring is easily available and can't be more than $15-20. What on earth were they thinking?

I believe that special S mainspring shape is all to do with trying to get "constant" torque across all states of wind. Is that how you understand it, Al?

Very interesting, thanks. Chris

 

Good stuff Al! thanks for taking the time to lecture (in a good way) all of us! and I do hope some of my watches reach your bench when service is required!